Control device for pneumatic-dispatch-tube apparatus



juiy 30, 1929. I s. OLSON 1,722,539?

CONTROL DEVICE FOR PNEUMATIC DISPATCH TUBE APPARATUS Filed Dec. 5, 1927 iii/denier.

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PatentedJuly 30, 1929.

UNITED STATES OFFICE.

smut. 015011, or" OAK PARK, ILLINOIS, assumes no smunr. OLSON & commit,

- I or CHICAGO, rumors, A conronarron or ILLINOIS.

CONTROL DEVICE FOR PNEUMATIC-DISPATCH-TUBE APRA RATUS.

Application me'a December 5, 1927. Serial no. 237,715.

. insertion of a carrier in the tube for trans mission, and the flow of air is again reduced to a partial flow after the discharge of the carrier from the tube.

The object of this invention is to provide means in a control device adapted to be operated b reason of the insertion of a carrier in the tu e, thus opening the valve which permits maximum flow of air, together with other means for retaining the valve in open position for a predetermined period which may be adjusted so that it is just suficient to per-' mit the carrier to be impelled through the tube to a point of dischargebefore the valve closes. It consists in certain features and elements of construction in combination, herein shown and described, and as indicated by the claims.

In the drawings: V

Figure 1 is a view illustrating somewhat diagrammatically a complete circuit of pneumatic dispatch tube apparatus equipped with the control device embodying the'present invention.

Figure 2 is a transverse sectional View of the control device taken substantially at a medial plane.

Fi re 3 is a detail face view of the valve mem er.

In the pneumaticdispatch tube apparatus circuit illustrated in Figure l, 10 indicates a suction or vacuum drum, connected by a pipe, 11, to a control device embodying the present invention as indicated generally at 12. It will be understood that the drum may be maintained under reduced pressure or partial vacuum by any suitable means, such as a suction pump (not shown). The opposite end of the device, 12, is connected by a pipe, 13, to the line proper, which consists of two transmission tubes, 14 and 15, constituting the out-going and return runs respectively for a pair of stations which theyserve.

- The control device is disposed in the line adjacent one of the stations and is adapted to regulate the carrier-impelling air flow through the tubes. At the station adjacent the control device,.the outgoing tube, 14, is fitted with a bell-shaped mouth, 16, forthe insertion of carriers to be transmitted to the other station, while the opposite end of said tube, 14 (at the other station is rovided with a spring-closed discharging a door, 17 through which the carriers may 'e discharged at said remote station. The flap door is hinged to a coupling, 18,-which connects the adjacent ends of said tubes to form a continuous passage from the control station to the remote station and return. This coupling is also provided with a spring closed flap, 19, on the opposite side for closing the end of the tube, 15, and also permitting insertion of carriers for transmission to the control station which carriers are discharged through a spring flap, 20, hinged to a header, 21, which serves as the interconnectin member in the line between the tubes and t e pipe, 13. These spring closed flaps provide substantially air-tight closures for the endsof the tubes so as to make a relatively closed continuous circuit from the mouth, 16, to the discharge end of the tube, 15, at the same end, so that the necessary suction may be produced for impelling a carrier through the tubes from either station to the other.

The control device, 12, which regulates the fiow of air through the tubes includes a housing, 25, which is provided with a valve, 26, disposed normally in a closed position as shown in the drawing, and adapted to be opened upon the introduction of a carrier in either tube. In systems of this nature, carriers are not being transmitted continuously, at least not for any great period of time; therefore, for purpose of efliciency, it is desirable to have full carrier impelling suction only when a carrier is in the tube, otherwise when the tubes are free, a partial or restricted flow through the line is suificient. This restricted flow of air through the tubes facilitates immediate transmissionof the carriers upon their introduction in the tubes, and is preferably obtained in a manner to permit the-valve to be closed during this idle period. The partial flow of air through the tubes may be accomplished by any suitable means, hereor more apertures, 27 and 28*, respectively, herein shown as four, spaced apart at equal angular distances, and adapted to be adjusted in relation to each other to regulate the partial flow of air through the system. B The operation of the valve, 26, is controlled a ,fiiixib e diaphragm, 30, positioned to form two chambers, 31 and 32. The chamber, 31, is provided with apertures, 33, for'venting the same at all times to atmospheric pressure,

While the chamber, 32, normally communi-- cates with thepressure in the line through a port, 34, when the Valve, 26, is closed. This port is controlled by means responsive to the flow of air in the line, as will hereinafter be described. The valve, 26, is mounted on a valve stem, 35, which extends into said chambers and through said diaphragm to which it is rigidly connected for actuation. The end of said stem beyond the valve is slidably suported'in a bearing, 36, integral with the ousing, 25, for positioning and aligning said valve; the other end of said stem beyond the diaphragm extends through and beyond the outer walls of the chamber, 31, and is provided with a spring, 37 positioned between said wall and an adjustable collar, 38, on the end of said stem. As is apparent from the drawing, this spring tends to normally maintain the valve in closed position.

The port, 34, of the chamber, 32, is controlled by a valve, 40, carried on the end of an arm, 41, of a bell crank pivoted at 42. The other arm, 43, of the bell crank normally extends obliquely upward and has secured to its outer end a baflie plate or vane, 44, positioned in the path of travel of air when the valve, 26, is open. This baffle plate may be of any desirable shape, such as disk, rectangular, etc; and preferably of a shape that will not unduly interfere with the flow of air through the system. A spring, 45, is connected to the bell crank arm, 41, and to a take-up rod, 46, extending through the wall of the housing and provided on its end with a nut, 47. It will be understood that when the valve, 26, is closed, the partial flow through the system will be inadequate to effect movement of the valve, 40, by the baflle, 44, and the tension on thespring, 45, may be adjusted to a desired strength to forestall any appreciable movement of the baffle until the flow of air through the system-obtains a predetermined velocity.

The chamber, 32, is never at any time under full atmospheric pressure; although it is in constant communication with the chamber, 31, by aby-pass or leak port consisting of a passageway, 49, connecting the ports, 50 and 51, of the respective chambers, 31, and 32. The passageway, 49, is controlled by a tapered valve, 52, adapted to be adjusted to re late the rate of air flow therethrough.

he operation of-the control device is as neumatic device which consists of a follows: The partial flow of air through the system causes a partial vacuum in the tubes and in the chamber, 32, due to the port, 34, being open when the valve 26, is closed. When a carrier is introduced into the tubes at either of the flap doors, 16 or 19, the air flow through the tubes becomes momentarily choked, thus increasing the vacuum in the tubes and in the chamber, 32. The chamber, 31, bein at atmospheric pressure, permits the diap ragm, 30, to respond to the vacuum in the chamber, 32, and move inwardly, shifting the valve stem, 35, thus opening the valve, 26, against the reaction of spring, 37. The opening of the valve, 26, permits full suction in the tube for impelling the carrier to its destination for discharge during which time the vacuum in the chamber, 32, is increased. Substantially at the instant of opening of the valve, 26, the resulting increased flow of air therethrough impinges against the baffle, 44, and forces the valve, 40, to seal the port, 34, of the chamber, 32, against the reaction of the spring, 45.

' It will now be clear that the chamber, 32, being closed from communication with the tube, retains the diaphragm in valve opening position. The by-pass valve between said chambers affords a steady, though limited flow of air at atmospheric pressure into the chamber, 32, at all times. I During the period that the chamber,'32, is cut ofi from the line (at which time the carrier is transmitted through the tube and discharged) the pressure in said chamber gradually increases to a point at which the diflerences in pressure of the, chambers is overcome by the spring, 37, which retracts the valve, 26, to closed position. After the valve, 26, closes, the sys tem returns to'a partial flow, and the reduced flow of air frees the baffle, 44, and permits the valve, 40, to open the port, 34, with the assistance of the spring, 45; then the device is in condition to again repeat the cycle. It will be understood that the by-pass valve may be so adjusted as to time closing of the valve, 26, immediately upon the discharge of the carrier from the tube.

I claim:

1. In a pneumatic dispatch tube system including a transmission tube for a carrier with an air line connecting it to a source of suction, a valve interposed in the line cont-rolling the flow of air therethrough, a restricted flow of air being permitted through the line when the valve is closed, a pneumatic device operably connected to the valve for opening the same, comprising a diaphragm, one side of which is subject to atmospheric pressure, the other side facing a chamber which is provided with a port normally venting the chamber to the pressure in the line, and means responsive to the flow of air in the line caused by opening of said valve, adapted to close said port and cut off communication of said chamber with the line.

- phragm,

2. In the combination defined in claim 1, said chamber having an atmospheric vent controlling the operation of said means for opening the port to line pressure.

3. In the combination defined in claim 1, a

.timing valve venting said chamber to atmosphere for controlling the movement of the diaphragm to valve closing osition.

4. In a pneumatic dispatch tu e system including a transmission tube for a carrier with an air line connecting it to a source of suction, a valve interposed in-the line controlling the flow of air therethrough, a restricted flow of air being permitted through the line when the valve 1S closed, a pneumatic device operably connected to the valve for opening the same, comprising a diaone side of which is subject to atmospheric pressure, the other side facing a chamber which is provided with a port normally venting the chamber to the pressure in the line, and means adapted to close the ort after a carrier has been inserted in the hue and thus has caused opening of the valve by reduction of pressure 1n the line and in said chamber, said means comprising a bafiie, a valve cooperatin with said port and connected to said ba e, being positioned for response to the increased flow of air in the line for controlling the port by its valve.

5. In the combination defined in claim 4, a spring normally tending to maintain said valve away from its port to vent the chamber to the line pressure.

6. In a pneumatic dispatch tube system comprising a transmission tube for a carrier with an air line connecting it to a source of suction,-a normally-closed valve interposed in the line adapted to be opened to permit maximum flow of air therethrough, said valve having an aperture therein for permitting a partial flow of air through the line when the valve is closed, and means for varying the size of said aperture to regulate the partial flow of air.

7. In the combination defined in claim 6 said means including an apertured member,

adapted to be adjusted relative ture in the valve for varyin to the aperthe efiective size of said aperture in the va ve.

8. In a pneumatic dispatch tube system including atransmission tube for a carrier with an air line connecting it to a source of suction, a valve interposed in the line controlling the flow of air therethrough, a restricted flow of air being permitted through the line when the valve is closed, a pneumatic device operably connected to the valve for opening the same comprising a diaphragm, one side of which is subject to atmospheric ressure, the other side facing a chamber w ich is provided with a port normally venting the chamber to the pressure in the line, said valve being moved to open position by the reduction of pressure resulting when a carrier is inserted in the line, and means operable independently of and substantially simultaneously with the opening of said valve by the increased flow of air in the line for retaining 'said valve in open position for a limited period.

9. In a pneumatic dispatch tube system including a transmission tube for a carrier with an air line connecting it to a source of suction, a valve interposed in the line controlling the flow of air therethrough, a retion of said chamber with the line, said chamber having an atmospheric vent for relieving the reduced pressure in the chamber to permit closure of the valve by its spring after a predetermined period.

10. In a pneumatic dispatch tube system including a transmission tube for a carrier with an air line connecting. it to a source of suction, a valve controlling the flow of air therethrough, means ieldingly holding said valve to its" seat, an a suction motor normally connected with said air line and adapt-- ed for opening said valve; a second valve controlling communication of said motor with the line; a baflie disposed in the path of the air through said line and responsive to the flow of said air when the first mentioned valve is open, together with means connecting said battle to the second valve for closing it when the first valve opens, and means for venting the suction motor to permit closure of said first valve by said yielding means.

11. In the combination defined in claim 10, yielding means normally tending to maintain said second valve in open position, and means for adjusting the tension on said yielding means.

SAMUEL OLSON. 

